Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1782/ERM-V1.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7415-ERM-V1.ps) >>/Users/jc/w/tmp/Tune-7415-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1782/ERM-V1.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-7415-ERM-V1.abc 143 ABC music file with the extracted tune(s)
Tune-7415-ERM-V1.ps 6 PostScript
Tune-7415-ERM-V1.txt 143 Plain-text file with the extracted tune(s)
Tune-7415-get.log 3984 Log file, useful mostly for debugging
Tune-74150-Hamilton_Kerr_MM2-V1.abc 158 ABC music file with the extracted tune(s)
Tune-74150-Hamilton_Kerr_MM2-V1.ps 6 PostScript
Tune-74150-Hamilton_Kerr_MM2-V1.txt 158 Plain-text file with the extracted tune(s)
Tune-74150-get.log 4328 Log file, useful mostly for debugging
Tune-74158-Feuillet_Essex_FtFIoD1.abc 159 ABC music file with the extracted tune(s)
Tune-74158-Feuillet_Essex_FtFIoD1.ps 6 PostScript
Tune-74158-Feuillet_Essex_FtFIoD1.txt 159 Plain-text file with the extracted tune(s)
Tune-74158-get.log 4364 Log file, useful mostly for debugging
These files should be available for 24 hours.